In patent application Ser. No. 311,063 entitled "Recovery of Metal Values from Manganese Deep Sea Nodules", filed on Dec. 1, 1972, by Lester J. Szabo, the teachings of which are incorporated herein by reference, a process is disclosed in which copper, nickel, cobalt and molybdenum are recovered from raw manganese nodules with an aqueous ammoniacal leach solution containing cuprous ions. The process disclosed in application Ser. No. 311,063 is a significant breakthrough in the metallurgical art in that it significantly expands the world's source of copper, nickel, cobalt and molybdenum. The process disclosed in application Ser. No. 311,063 has come to be called the "cuprion" process.
The cuprion process for recovering copper, nickel, cobalt and molybdenum from manganese deep sea nodules includes the step of contacting ground manganese nodules with an ammoniacal leach solution containing cuprous ions in a reaction vessel to reduce the manganese oxides in the nodules to enable metal values such as copper, nickel, cobalt and molybdenum to be solubilized. The nodule residue is washed with an ammoniacal ammonium carbonate solution to remove these entrained metal values from the residue. The reduction liquor can be recycled to the reaction vessel in which the manganese nodules are added. To maintain a sufficient amount of cuprous ions, a reducing gas, such as carbon monoxide, is passed through the reaction vessels.
To commence the process disclosed in patent application Ser. No. 311,063, the cuprous ions may be charged into the reactors by adding a cuprous salt or by reducing cupric salts to obtain the cuprous ions.
The major disadvantage of the known prior art startup procedure is that it is slower than the start-up of the present invention. Furthermore, the start-up procedure of the process disclosed in patent application Ser. No. 311,063 is more expensive than the process of the present invention because it necessitates the use of increased amounts of carbon monoxide or other chemicals such as cuprous salts.